It has long been a feature of many types of compositions, including cosmetic compositions, that they comprise a fragrance oil for the purpose of delivering a pleasant smell. This can improve the overall consumer acceptance of the composition or mask unpleasant odours. In fact, it can be the sole purpose of some compositions to impart a pleasant odour to the skin, hair or other suitable substrate.
Fragrance oils used within compositions usually comprise many different perfume raw materials. Each perfume raw material used differs from another by several important properties including individual character, volatility and the olfactory detection level (known as the odour detection threshold). By bearing in mind these different properties, and others, the perfume raw material can be blended to develop a fragrance oil with an overall specific character profile. It is usual that the character is designed to alter and develop with time as the different perfume raw materials evaporate from the substrate and are detected by the user. For example perfume raw materials which have a high volatility and low substantivity are commonly used to give an initial burst of characters such as light, fresh, fruity, citrus, green or delicate floral to the fragrance oil which are detected soon after application. Such materials are commonly referred to in the field of fragrances as “top notes”. By way of a contrast, the less volatile, and more substantive, perfume raw materials are typically used to give characters such as musk, sweet, balsamic, spicy, woody or heavy floral to the fragrance oil which, although may also be detected soon after application, also last for longer. These materials are commonly referred to as “middle notes” or “base notes”. Highly skilled perfumers are usually employed to carefully blend perfume raw materials so that the resultant fragrance oils have the desired overall fragrance character profile.
To date, the physical characteristics of the perfume raw materials themselves have limited the overall fragrance character profiles that can be created by perfumers. One such limitation is that it has only been possible to develop fragrance oils which impart a “top note” character for a short period of time. This is because the top note perfume raw materials are highly volatile and are therefore rapidly released from the substrate. As such, the longer lasting element of a fragrance character profile has been achieved by using middle and base notes which in turn restricts the achievable characters to musk, sweet, balsamic, spicy, woody or heavy floral and the like. Blending of higher levels of top note perfume raw materials to a fragrance oil does not improve the long lasting nature of the light, fresh, fruity, citrus, green, or delicate floral “top note” fragrance character, but instead could result in a stronger initial burst which again quickly evaporates and does not therefore last.
It is known that consumer preference for fragrance compositions is mostly driven by the initial “top note” character. It is therefore desirable to have a fragrance wherein the “top note” character is long lasting and perceived throughout use (ie after application of the composition to the substrate). It is also desirable to be able to create new to the world fragrance character profiles wherein one, or several, well recognised “top note” characters are maintained overtime such that a unique long lasting, “top, middle and base note” character is created. As such, it would be advantageous to be able to create a fragrance oil which will impart, in a new way, top note fragrance characteristics to a composition, particularly a cosmetic composition, wherein the top note character is released from the composition over a substantial period of time, and, in particular, where the top note fragrance character remains detectable at least two hours after application.
In the past, many attempts have been made to delay the volatility profiles of fragrance oils within many types of compositions to extend the overall fragrance effect. For instance the fragrance oil may be formulated to include a higher proportion of perfume raw materials with a low volatility and which are therefore more substantive on the substrate. However, as discussed above, this restricts the fragrance character that can be achieved over time. Another approach has been to chemically, and reversibly, modify the perfume raw materials to a pro-perfume compound which is disclosed in patent applications WO 98/47477; WO 99/43667; WO 98/07405; WO 98/47478; all of which are incorporated herein by reference. The resultant pro-perfumes are not themselves volatile but, after the chemical modification is reversed, usually by hydrolysis upon application to the substrate, the perfume raw material is released and can then evaporate in the usual way. In these examples the release rate of the perfume raw materials is controlled by the reaction rate of the pro-perfume to perfume raw material transformation.
Further disclosures have discussed improving the overall longevity of a fragrance by delaying the evaporation of the fragrance oils. A wide variety of techniques have been disclosed among them encapsulation of the perfume raw materials for example within capsules (disclosed in JP-A-58/052211, EP-A-303,461), absorbing the materials to a surface for example by using carbon or zeolites (disclosed in U.S. Pat. No. 6,033,679), occluding the release of the perfume raw materials for example by the formation of a film (disclosed in U.S. Pat. No. 3,939,099) and complexing the perfume raw materials for example by using cyclic oligosaccharides. The prior art on this latter method includes JP-A-6/287127 and JP-A-8/176587 which disclose use of hydroxyalkylated cyclodextrins within cosmetic compositions to sustain the effect of the fragrance; and JP-A-8/183719 and JP-A-10/120541 which discloses a combination of cyclodextrin encapsulated fragrance and non encapsulated fragrance within a deodorant composition for prolonging the fragrance duration to at least 2 hours, all of which are incorporated herein by reference.
Whilst the compositions and disclosures of the prior art provide useful teachings for prolonging the overall fragrance character of a composition the approaches still have limitations. The pro-perfume approach is limited by those chemical modifications that can suitably be made to the perfume raw materials. In addition, the prior art is restricted by pro chemistries used, or by the use of low levels of pro perfumes, thus preventing the development of a fragrance oil which exhibits a broad range of top note characters over time. On the other hand, entrapment materials, when used in the traditional way, interact with a broad range of perfume materials including top, middle and base notes prolonging the overall character of the whole fragrance. As such the prior art does not sufficiently teach how to preferentially delay evaporation of a large range of top note perfume materials within a single fragrance composition, particularly a cosmetic composition. In addition since, in general, entrapment such as that described suppresses the evaporation of only a relatively small amount of the perfume raw materials, the low level of delayed release is often not noticeable to the user. As such the prior art does not adequately teach how to provide a fragrance with long lasting and noticeable “top note” character.
Surprisingly, it has now been found that compositions, particularly cosmetic compositions, comprising a fragrance oil and a material which is able to delay the evaporation of the fragrance oil, wherein the weight ratio between the top note perfume raw materials of the fragrance oil and the entrapment material within the association that exists between them on the substrate is within the range of 1:20 to 20:1, and preferably in conjunction with a balance of perfume raw materials with a low odour detection threshold, can be used to create a long lasting fragrance character profile which has prolonged, and noticeable, “top note” characteristics. In addition, it has been found that within such compositions long lasting “top note” character can be combined with “middle and base note” characters to uniquely achieve a long lasting fragrance character profile with a broad spectrum of “top, middle and base notes” that it would not have been possible to develop using traditional perfumery.
While not wishing to be bound by theory, it is believed that when a composition according to the present invention is applied to a substrate an association exists between the perfume raw materials and the entrapment material such that the evaporation of the perfume raw materials is delayed. Over time, this association breaks down resulting in release of the perfume raw materials. Since the composition comprises a fragrance oil which has been developed with a high level of perfume raw materials with “top note” fragrance character, the “top note” character continues to be experienced by the user over time. In addition, since the fragrance oil can preferably be developed with a balance of perfume raw materials with a low odour detection threshold, the user will experience a meaningful and novel fragrance character profile over time. This is because the perfume raw materials continue to remain detectable even though only a relatively small level is being released.
In addition, because the volatilisation rate of any given ingredient has, until now, been mainly related to its own boiling point, it has not been possible to obtain recurring and intermittent blooms (or pulses) of specific fragrance characters throughout the complete usage period. Surprisingly it has now been found that, once a substrate has been fragranced using a composition of the present invention, the fragrance can be refreshed over time, either naturally or deliberately, to release periodic and unexpected blooms of one or several fragrance characters. Whilst not wishing to be bound by theory, it is believed that this can be achieved by enhancing the natural decomposition rate of the fragrance oil entrapment material association for example by application of water, either naturally by breathing on the complex or by sweating, or artificially by spraying on a mist and the like. This “activation” results in the user experiencing a noticeable bloom of fragrance character. Surprisingly it has been found that it is possible to “activate” this complex, and thus generate fragrance blooms, several times during the wear. It is also believed that the negative consumer perception of becoming used to a scent can be minimised or prevented as a result of periodic “activation” resulting in an unexpected perceptible altering in the overall character of the fragrance.
It is an object of the present invention to provide compositions, particularly cosmetic compositons, which impart a long lasting and noticeable light, fresh, fruity, citrus, green or delicate floral “top note” fragrance character to the substrate on which they are applied. This, and other objects of this invention, will become apparent in light of the following disclosure.